Belt shifter



May 18, 1948.

G. B. SIMONSON BELT SHIFTER Filed Aug. 25, 1946 2 Sheets-Sheet lIN'VENTOR fi eazya B. 512220229022, BY W MaQNE-LYS May 18, 1948. G. B.SIMONSON BELT SHIFTER Filed Aug. 23, 1946 2 Sheets-Sheet 2 INVENR 23.5

n deal e BY M ATTORNEYS Patented May 18, 1948 umrso STATES PATENT orricsBELT SHIF'IER George B. Simonson, Hawthorne, Calif.

Application August 23, 1946,

3 Claims. 1

This invention relates generally to means used in the shifting ofmachine belts to change the speed of operation of a machine; and moreparticularly to an intermediate stepped pulley assembly adapted to beinstalled between the two driving and driven pulleys of such as a drillpress or the like machine, the primary object of the invention being toprovide a device of this character which greatly facilitates theshifting of the belts from one step of the intermediate pulley toanother to vary the driven speed of the machine, said device havingmeans enabling the stepped pulley to be moved toward the driving anddriven pulleys of the machine to slacken the belts sufilciently topermit easy shifting thereof from one step of the intermediate pulleythereof without prying the belts out of the pulley grooves.

Another important object of this invention is to provide a device of thecharacter indicated above which has means, operative upon withdrawingthe stepped pulley away from the driving and driven pulleys of themachine for tightening the belts after a shift thereof, forautomatically centering the stepped pulley between the driving anddriven pulleys, as said stepped pulley is moved in the belt tighteningdirection, so that equal tension on the two belts is obtained.

Another important object of this invention is to provide a device of thecharacter indicated above in which the stepped pulley is manipulatedinto both the belt slackening and belt tightening positions by means ofa single hand lever, and in which a single hand lever is employed forlocking the stepped pulley in adjusted belt tightening position, and forreleasing the stepped pulley therefrom.

A further object of my invention is to provide a device of the characterindicated above in which the stepped intermediate pulley can be arrangedrelative to the driving and driven pulleys, so that the belts can bechanged easily and readily.

Other important objects and advantageous features of this invention willbe apparent in the following detailed description and "appendeddrawings, wherein merely for the purposes of disclosure herein, aspecific but non-limitative embodiment of this invention is set forth.

In the drawings- Figure l is a general top perspective view.

Serial No. 692,428

Figure 2 is an end elevation, looking from right to left in Figure l,and partly broken away'to show the extended shoulder formation ofcertain of the pivot studs. g

Figure 3 is a top plan view with the stepped pulley removed.

Figure 4 is a side elevation, looking from left to right in Figure 2,and,

Figure 5 is a fragmentary plan view, on a reduced scale, showinginstallation of the device on a machine between the driving and drivenpulleys thereof.

In using the intermediate stepped or cone pulley devices now availablefor lowering or raising the speed of operation of such machineas drillpresses and the like, it is necessary to employ extremely short V-belts,the shifting of which on the intermediate pulley is a very difficultoperation. Further, such intermediate pulley devices are fixedlyinstalled on the center line of the driving and driven pulleys of themachine, so 7 that, in the case of a drill press, for example, it is notpossible to raise or lower the head of the drill press, as may bedesirable or necessary in certain circumstances.

The device of the present invention eliminates these difficulties, whenapplied toa drill press or any other machine employing driving anddriven pulleys, whether the V-type or flat type of belts are used, bymeans of the structural and functional arrangements of parts hereinafterdisclosed, which include a floating mounting of the stepped pulley.

Referring to the drawings in detail, the numeral 6 generally designatesthe base of the de-' vice disclosed herein, which is in the form of abracket attachable to a suitable part of the frame of any machine (notshown) with which the present device may be associated, in a positionsubstantially midway between the driving and driven pulleys 1 and 8thereof, as shown in Figure 5.

The fore end of the base bracket 6 is bifurcated or forkedto define thesubstantially parallel arms 9 and 10, which are vertically traversednear their inner ends by the plate pivot stud II and the tightening stud[2, respectively, these studs having their heads preferably flush in thetops of the arms and having their shanks depending to traverse thegenerally rectangular plate, which is generally designated l3.

The shank of the plate pivot stud it includes an enlarged diametershoulder M which turns in a conforming opening formed adjacent to onecorner of the plate l3, as indicated in Figure 3, the lower end of saidshoulder projecting below the bottom of the plate for contact by the nutl5 which is threaded on the lower end of the shank, whereby swinging ofthe plate l3 relative to the base 6 is not restricted although the nut[5 may be fully tightened. V

The shank of the tightening stud i2 is plain and has threaded thereonbelow the plate I3 a nut I6 adapted to join against the bottom of saidplate to lock the plate l3 and base 6 together in selected positions.The nut [5 has a lever handle I! having an enlarged ball handle iii.

The tightening stud l2 depends through and can move along a slot I9formed through the plate I 3 and curved with the pivot stud H as itscenter of curvature.

On top of the plate l3 and positioned between the arms 9 and it of thebase ii is the carrier 2!] of about the same cross section and width asthe base arms 9 and I0 and about'halfi'theirlengthi The forward end ofthe carrier is traversed by a carrier stud 2| which depends through 'a'hole formed in the forepart of the plate 53; The;

shank of the stud 2! has an enlarged shoulder 22 comformably received bythe hole. inthe plate and depending therebelow; as shownin Figure '2,with a nut 23 tightened onthe lower'part of the stud against theshoulder 22, whereby clearance between" the nut 2 3. and the plate 53.is provided to insure" free'movement of the carrier stud 2i and the nut23 relative.- to the. plate i3.

Rising from the inner end of the'carrier 2c is'the stubshaft 25rotatably carrying a cone cit-stepped intermediate pulley 2d; The platei3 hasalever handle 21 threaded, as indicated at 28; inthefore edge ofthe plate I3 .near the same side-as the plate pivot. stud H, with a ballhandle 29* at its outer end. The arms 9 and I 0" prevent the carrier2ilfrom over pivoting to either'side, and provide surfaces, againstwhich the plate it will bear under the tension. otthe belts.

Asindicated in Figures 1, 2 and 5, the driving pullcyls may have itsbelt 3i]: in one of the upper steps or grooves of the. stepped pulley28, with the belt 31 of the driven pulley in a lower step or groove ofthe. pulley 2t.

To operate. the device of the. invention from the operated. positionshown. in Figure 5, wherein the.

belts ilil. and 3! arev equally tensioned. inoperatingrelation, thehandle. H on the tightening nut it is swung in theloosening directionabout a quarter of a turn or more, so as to permit the tension of thebelts 3G and 31' to pullor pivot the plate 13:, and hence. the carrier29 and stepped pulley 26. toward the pulleys l and 8.

After shifting. the beltsfor the desired speed change. the lever 21 isswung ina direction tending to: tightencthe belts 3H and 31., so thatthe carrier 20, which is free on its. pivot stud H,

can. automatically adjust itself to put exactly the. same tension oneach. of the belts 3i] and 3|. The handle H is then swung in thedirection to tighten the nut Iii and lock the plate l3. andbase.6-together in the new position.

It be evident. from: the foregoing, that the device oithepresent.invention is to be mounted onthe machine with which it is used, in aposition somewhatd'lsplaced' from. rather thanon the. center linebetween the. two pulleys of the machine;

It is also obvious thatlthe belt speed changes can. be mademore easilyand quicklywith the stepped pulley of the present device in the beltloosening position, and: the belts aresubjected to less wear and; tear,since the belts then-do not clearly, that the belts. 30-. and .3 can beeasily" side of its pivotal 4 removed and replaced, after the plate I3is adjusted, so that the two belts are slackened.

The above described device is also adapted to set the intermediatepulley, so that the belts are arranged to function in the mostadvantageous way in relation to the load imposed on the driven pulley.

What is claimed is:

1. An intermediate stepped pulley device for use onamachine having a.drivingpulley and a driven pulley each having a belt, said devicecomprising. a relatively stationary-base adapted to be mounted onsaidmachine between and at .oneside of said driving and driven pulleys, aplate pivoted on said base, a carrier freely pivoted on said plateandccarrying a stepped pulley at one point in grooves of which the beltsof the driving and driven pulleys are adapted to be selectivelypositioned, handled looking means for holding said plate in a selectedpivoted positionrelative .to said base, and handled meansfor swingingsaidplaterelative tosaid base while said locking means is in unlockedposition, for moving said plate and hence said carrier andstepped pulleyin a direction toward the driving and driven. pulleys so as to loosentheir belts to enableeasily shifting the belts'to other groovesof saidstepped pulley or removing and replacing said belts, andin a directionaway from the driving, and driven. pulleys. so as to tighten-thebeltsand permit said. carrier to pivot-to carry said stepped. pulley to aposition in Whichthe tightening tension on the. belts is equalized.

2. Anintermediate stepped pulley device for use witha machine having.belt equipped driving and driven pulleys, said device comprising abracket for stationary attachment to the machine. at. one side of.anintermediate said. driving and driven pulleys, said bracket comprisinga. fiat base positioned in a plane parallel to the belts and bifurcatedat its outer end to define a pair of spaced arms, a. flat. platepositioned beneathsaid arms, aplate pivot studdepend'ing irom' one ofsaid arms and traversing said. plate for pivoting said plate on saidbase, a tightening, stud: depending from. the other of said arms.through. and movable along a slot formed in said plate, said slot beingcurved with said plate pivot studas its center of curvature ahandleequipped locking. nut on the lower end of. said tightening studadaptedto be turned thereon against the V underside of said plate to lock. saidplate and said. base together in a selected pivoted position of saidplate, a floating carrier bar on said.

from said; diivi ing the belts and to permit said floating carrier platebetween the arms of said base, a carrier pivot pivoting one end of saidcarrier bar. to swing crosswise between said arms, a stepped" pulley onthe opposite end. of said carrier bar in grooves of which said drivinand driven pulley belts are adapted to be selectively p'o'si tioned,andia handleon said plate enabling said plate to be swung on said platepivot stud-relative to said base, when 7 said locking nut is loosened,in a direction toward said driving and driven pulleys for looseningtheir belts to ena'bl'e them to. be shifted. to other grooves 01 saidstepped pulley, and in the opposite direction awayhg and driven pulleysfor tighten-- and movable said slot being curved with bracket forstationary attachment to the machine at one side of an intermediate saiddriving and driven pulleys, said bracket comprising a flat basepositioned in a plane parallel to the belts and bifurcated at its outerend to define a pair of spaced arms, a fiat plate positioned beneathsaid arms, a plate pivot stud dependin from one of said arms andtraversing said plate for pivoting said plate on said base, a tighteningstud depending from the other of said arms through along a slot formedin said plate, said plate pivot stud as its center of curvature, ahandle equipped looking nut on the lower end of said tightening studadapted to be turned thereon against the underside of said plate to locksaid plate and said base together in a selected pivoted position of saidplate, a floating carrier bar on said plate between the arms of saidbase, a carrier pivot pivoting one end of said carrier bar to swingcrosswise between said arms, a stepped pulley on the opposite end ofsaid carrier bar in grooves of which said driving and driven pulleybelts are adapted to be selectively positioned, and a handle on saidplate enabling said plate to be swung on said plate pivot stud relativeto said base, when said locking nut is loosened, in a direction towardsaid driving and driven pulleys for loosening their belts to enable themto be shifted to other grooves of said stepped pulley, and in theopposite direction away from said driving and driven pulleys fortightening the belts and to permit said floating carrier to swingrelative to said base and said plate into a position in which thetightening tension is equalized between the belts, said arms forming astrengthening support for the plate under the tension of the belts.

GEORGE B. SIMONSON.

